In its ongoing effort to crack down on the nation’s prescription-drug epidemic, the U.S. Drug Enforcement Administration has gone after doctors, pharmacists, pharmacy chains, wholesale drug suppliers — and now FedEx and UPS.

Even though the DEA will not confirm it is engaged in the probe, both companies have disclosed in corporate filings that they are targets of a federal investigation related to packages shipped from online pharmacies.

Based on the allegations, it appears federal officials are suggesting the shipping companies take responsibility for the prescription drugs inside packages they are transporting.

FedEx officials have called the California-based probe “absurd and deeply disturbing” and a threat to customers’ privacy.